I remember being at PIR on Ferrari track days, listening to the men who owned Ferrari's of the same era. Double clutching was what they had to do to be fast.If you don't believe me, believe Phil Hill from an article he wrote for Road and Track: http://www.roadandtrack.com/racing/ferrari-gto-history

"I can't, however, be as enthusiastic about the gearbox, which has Porsche baulking-ring type synchros. This change may have been an advantage to the younger drivers (and customers) who weren't adept at proper double-clutch downshifting, but the synchros slowed the entire gear-changing process. In comparison with other Ferrari racing transmissions, the GTO's long throws and heavy feel seemed a step backward.

That gearbox, however, was the only thing about the GTO that wasn't a pleasure. Looking at the stark interior now, the car looks slightly unfinished, but in 1962 we couldn't have cared less. Here was a GT that had quickly taken us out of the era in which a driver was constantly balancing a car's virtues against its vices, to that time when the basic vices were gone and our only job was to make maximum use of the virtues. A GT with handling that had neither difficult understeer nor treacherous oversteer, and that was, best of all perhaps, predictable and confident."